Non stoichiometric thin tin oxide films have been deposited using the PACVD technique in a RF glow discharge diode or triode reactor at low pressure (15 Pa) and at low temperature (25–100°C). The films deposited in the diode configuration were amorphous and presented a high transmittance (95%) in the visible region. The conductivity of the films deposited in the triode configuration can be increased by 4 orders of magnitude with respect to the ones deposited in the diode configuration (from 0.01 to 100 ω−1 cm−1) with a decrease of the gap energy (from 3.5 to 2.5 eV). This increase of the conductivity was accompanied by a slight decrease of the grain size (95 to 45 nm). The very small grain size of the deposited films makes them excellent candidates for gas sensors due to their good sensitivities to different molecules such as ethanol and propane.